#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

#define N 2
#define NUM 1024

using namespace std;

void Writer(int wfd)
{
    string s="hello,I am child";
    pid_t self=getpid();
    int number=0;

    char buffer[NUM];
    while(true)
    {
        sleep(1);
        buffer[0]=0;
        snprintf(buffer, sizeof(buffer), "%s-%d-%d", s.c_str(), self, number++);
        write(wfd,buffer,strlen(buffer));
    }
}

void Reader(int rfd)
{
    char buffer[NUM];
    int cnt=0;
    while(true)
    {
        buffer[0]=0;
        ssize_t n=read(rfd,buffer,sizeof(buffer));
        if(n>0)
        {
            buffer[n]=0;
            cout << "father get a message[" << getpid() << "]# " << buffer << endl;
        }
        else if(n==0)
        {
            printf("father read file done\n");
            break;
        }
        else
            break;
        cnt++;
        if(cnt>5)
            break;
    }
}

int main()
{
    int pipefd[N]={0};
    int n=pipe(pipefd);
    if(n<0)
        return 1;
    pid_t id=fork();
    if(id<0)
        return 2;
    else if(id==0)
    {
        //child
        close(pipefd[0]);

        Writer(pipefd[1]);

        close(pipefd[1]);

        exit(0);
    }
    //father
    close(pipefd[1]);
    
    Reader(pipefd[0]);
    close(pipefd[0]);
    cout << "father close read fd: " << pipefd[0] << endl;

    int status=0;
    pid_t rid = waitpid(id, nullptr, 0);
    if(rid<0)
        return 3;
    cout << "wait child success: ";


    close(pipefd[0]);
   // sleep(5);
    cout << "father quit" << endl;
    return 0;
}